# Objectives
+ Add and replace data in a table using the **`INSERT`** and **`REPLACE`** statements
+ Use the **`UPDATE`** statement to modify existing data in a table
+ Avoid and handle duplicate records​
+ Remove data from a table with the **`DELETE`** and **`TRUNCATE`** statements
+ Learn what transactions​ are and how to use them
+ Use pessimistic and optimistic locking​
+ Learn about SQL injections risks and how prepared statements​ can be used to avoid this

------------------------------------------------------------
[no notes]